Thursday, 21 March 2013

Making MIDI hi-hat controller from unused bass drum pedal

Recently one of my friends bought an electronic drum set made by polish manufacturer "DIG DRUM". The drum set is very good and combined with the Alesis triggerIO works really well.

Unfortunately the pedal for controlling the hi-hat open/close signal was not included in the set. After a quick search, I've discovered that the circuit for the controller is trivial, so I decided to build my own.

The circuit for setting the pedal state consist only off a potentiometer and a cable which connects it to one of the IO ports of the trigger interface. You can find the diagram on this page.

For the pedal I've used a part of a twin bass drum pedal set, which was no longer used.
In order to be able to rotate the potentiometer, it needs to be mounted to the axis off the pedal. To achieve that I've created a stand from a piece of plexiglass and a metal plate.

The stand with the potentiometer and the socket:

The potentiometer is connected with a 1/4 stereo jack socket using a short wire:

The part which connects the axis of the pedal with the potentionemter. A few screws and metal pads mounted together:

...and the whole construction:

It works pretty well for now, but I suppose that the potentiometer will not live for too long in this kind of application :-)

2 comments:

Pretty ingenious! Carbon pots do wear fast, but for a digital application you won't have a "scratchy" pot problem. But over time, the worn out tracks may output 0 volts or have erratic output. I'd look into using a Conductive Plastic potentiometer, like a Bourns 91 series.